[Proposal] Add instance Monoid a => Monoid (Const a b)

[Edward Kmett]

That is a pretty solid argument for moving Compose.

Especially as Traversable will be transitioning into the Prelude in 7.10.

-Edward


On Sat, Oct 12, 2013 at 1:57 PM, Gershom Bazerman <gershomb at gmail.com>wrote:

> On 10/12/13 1:32 PM, Edward Kmett wrote:
>
>>
>> Between moving Identity into base and removing Constant it would mean
>> that transformers would then only have to contain ...well.. transformers. =)
>>
>> -Edward
>>
>>  Well, not quite. Compose should migrate into base at well at some point,
> I think. Especially since currently we have traversable laws in base using
> a datatype _not_ in base!
>
> I can see an argument in favor of Product as well, but also an argument,
> perhaps, that the product of two functors is somewhat less common than
> their composition.
>
> I consider the whole "polynomial functor toolkit" as pretty basic. But I
> can see a slippery-slope danger that we should only bring in those
> components that make other "basic" parts of base more elegant.
>
> Also, we should bear in mind that "growing" the algebraic part of base
> (Traversable, Functors, etc.) doesn't necessarily go against the spirit of
> then taking these slightly larger units of conceptual functionality and
> splitting them out from "core-base" in the next go-round.
>
> --Gershom
>
> ______________________________**_________________
> Libraries mailing list
> Libraries at haskell.org
> http://www.haskell.org/**mailman/listinfo/libraries<http://www.haskell.org/mailman/listinfo/libraries>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.haskell.org/pipermail/libraries/attachments/20131012/755bff6b/attachment.html>